With a random Staffel (early/mid war) in mind. In addition to every pilots 'personal' aircraft (with their own victory markings/personal emblems and what not) in the Staffel, was it common practise for a typical Staffel to have maybe one or two additional aircraft present for stand-in purposes or maybe use under circumstances better suited to that particular aircraft?

I'm still reading up on German nightfighter units, and I've read about several occasion where at one point a certain pilot flies say a BF-110 (apparently his 'personal' mount) and then is ordered to fly a Dornier for his next mission.

To have one or two extra aircraft available would make sence to me. Suppose one aircraft or another is better suited to certains weather conditions or perhaps due to the fact that one's personal aircraft is in maintainance/repairs it would make sence to be able to grab the 'extra' mount if on duty at that time.

I've indeed read about Helmut Lent and how he flew just about everything that had two wings and an engine and managed to shoot down allied bombers with it. Other Nightfighter pilots from that era also appear to have qualifications to fly different types. However the pilot I'm particularly interested in is Paul Gildner. He flew 109's (helle nachtjagd apparently sometime in 1940) BF-110 (which appears to me to be his mount of choice) and Dorniers.

I've read about him being rebased from Leeuwarden to to Gilze Rijen in early '43 (shortly before he was KIA) to take over command of some unit after it's formar CO was KIA. Sometime in February '43 he went to fly some operation from Gilze Rijen and achieved a victorie or two. Interesting in this respect is the fact that his bord-funker (who survided Gildners crash a few days later) mentions how all their electronics failed (Lichtenstein/homing devices etc.) during that particular mission. On top of that they were called back to base early due to ground fog. So they had to land in the fog with busted up electronics (they couldn't pick up the Gilze Rijen beacon apparently) So, Gildner wasn't comfortable with landing on Gilze Rijen and decided to fly to Leeuwarden, from which he operated for over two years and knew like the back of his hand so to say.

Gildner indeed ended up on Leeuwarden again, and his CO agreed upon Gildner staying on Leeuwarden for a day or so. Note that he was apparenly a much loved and respected pilot and all his friends, fellow pilots etc. were based on Leeuwarden and he got along very well with the Lent. So he stayed a few days on Leeuwarden and was ordered to fly some mission from Leeuwarden in what is described by his bordfunker as 'the aging Dornier'

So, paired with indeed the exploits of such people as Helmut Lent, Ludwig Becker, and how they flew so many different planes, it seems as though the unit based on Leeuwarden at the time had one or two extra aircraft for 'stand-in' purposes/testing purposes so to say (take Ludwig Beckers victory of august '41 in a Do-215, the first to be equipped with an early Lichtenstein model). Just to further explain my train of thought, remember the electronics in Gildners 110 apparently were a mess, and he was thus ordered to fly the Dornier (perhaps while mechanics/technicians maybe looked into the issues with his BF-110, or that is at least my assumption). Ofcourse Gildner too was one of those early innovators of the Nachtjagd together with Lippe Weisenfeld, Helmut Lent, Ludwig Becker, etc. and at the time they were probably among the most experienced and qualified the Nachtjagd units had to offer, so he probably was qualified to fly different planes too, but still...

Also, if you discard the fact that it is a different type in this case, but turn it into the same A/C type...was it common practise for a staffel to have an extra A/C or so on the scene? Or was this an anomaly in respect to this Nightfighter unit as they were among the most experienced the Luftwaffe had to offer, and as such had the luxury/priviledge so to say to have some extra A/C to be used according to the units needs.